As more and more mobile phone manufacturers launch full-screen products, consumers begin to pay attention to this new form of future mobile phones, i.e. full screen mobile phones, and the times for full-screen finally comes. It is an inevitable development trend to replace physical keys on a mobile phone with virtual keys, so that not only the stunning visual effect and the amazing appearance brought by a full screen are ensured, but also more practical functional features are provided. The virtual button refers to that when a key-pressing is performed in a key area by a user, a mobile phone responds with short-time vibration satisfying a requirement on vibration sense intensity. In order to achieve this short-time vibration effect, motor brake is one of the key techniques, which precisely controls to weaken the motor vibration until it stops. In the prior art, the resonance frequency of the motor is obtained by monitoring the zero-crossing point of the back electromotive force when the motor is freely vibrating, and a signal having the resonance frequency and with a polarity opposite to the back electromotive force is input to the motor, so to achieve the braking.
There are at least the following problems in the prior art: there are a variety of variations in the frequency and amplitude of the short signal waveform for implementing vibration effect by the virtual keys of the mobile; during actual use, brake implemented by using a single resonance frequency signal is not efficient, and cannot quickly stop motor vibration; and there would be a reverse acceleration if the signal amplitude is incorrectly adjusted, and consequently, the motor cannot have a good brake effect.